The ballparks include the homes of the Minnesota Twins, Baltimore Orioles, Milwaukee Brewers, Oakland A's, Pittsburgh Pirates, Detroit Tigers and Chicago Cubs. They join the New York Mets, San Francisco Giants and Kansas City Royals, all which began accepting Passbook tickets last fall.

MLB says that three additional parks will announce Passbook support this season, but they're not ready to do so just yet. MLB noted that Apple's Passbook app was the delivery method of choice for 12 percent of e-tickets purchased last season.